CAN COMMUNICATION SYSTEM Check Chassis Local Bus Line for Short to GND

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and GND when there is no resistance between terminal 19 (CAYH) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 20 (CAYL) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Symptom	Trouble Area
There is no resistance between terminal 19 (CAYH) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 20 (CAYL) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.	Short to ground in CAN main bus wire Short to ground in CAN branch wire Central gateway ECU (network gateway ECU) Rear steering control ECU1 Absorber control ECU Front steering control ECU2 Driving support ECU assembly*3 Rack and pinion power steering gear assembly Skid control ECU assembly No. 8 CAN junction connector No. 17 CAN junction connector No. 18 CAN junction connector No. 1 CAN junction terminal

Symptom

Trouble Area

There is no resistance between terminal 19 (CAYH) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 20 (CAYL) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Short to ground in CAN main bus wire
Short to ground in CAN branch wire
Central gateway ECU (network gateway ECU)
Rear steering control ECU*1
Absorber control ECU
Front steering control ECU*2
Driving support ECU assembly*3
Rack and pinion power steering gear assembly
Skid control ECU assembly
No. 8 CAN junction connector
No. 17 CAN junction connector
No. 18 CAN junction connector
No. 1 CAN junction terminal

*1: w/ Dynamic Rear Steering System
*2: w/ Variable Gear Ratio Steering System
*3: w/ Pre-collision System

WIRING DIAGRAM

for LHD
for RHD

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

Note

Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

Click here
Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

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Some parts must be initialized and set when replacing or removing and installing parts.

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After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

DTC check procedure: Turn the engine switch on (IG) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.
After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.

Click here

Tech Tips

Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.
When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE

CHECK VEHICLE TYPE

Check vehicle type.

Result

Result	Proceed to
for LHD	A
for RHD	B

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 18 CAN JUNCTION CONNECTOR) Click here

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 17 CAN JUNCTION CONNECTOR)

Disconnect the cable from the negative (-) battery terminal.

*a	Front view of wire harness connector (to No. 17 CAN Junction Connector)
*b	Front view of DLC3
*c	to No. 18 CAN Junction Connector
*d	to Absorber Control ECU
*e	to Central Gateway ECU (Network Gateway ECU)

Disconnect the No. 17 CAN junction connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
X114-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 18 CAN junction connector
X114-12 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 18 CAN junction connector
X114-2 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Absorber control ECU
X114-13 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Absorber control ECU
X114-3 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Central gateway ECU (network gateway ECU)
X114-14 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Central gateway ECU (network gateway ECU)

Result

Result	Proceed to
OK	A
NG (Central gateway ECU [network gateway ECU] CAN main wire)	B
NG (No. 18 CAN junction connector CAN main wire)	C
NG (Wire to ECU or sensor)	D

REPLACE NO. 17 CAN JUNCTION CONNECTOR

CONNECT CONNECTOR Click here

GO TO STEP 16 Click here

CONNECT CONNECTOR

Reconnect the X114 No. 17 CAN junction connector.

Result

Proceed to
NEXT

CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 17 CAN JUNCTION CONNECTOR)

Front view of wire harness connector

(to Central Gateway ECU [Network Gateway ECU])

Front view of DLC3

Disconnect the central gateway ECU (network gateway ECU) connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
P59-19 (CAYH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
P59-20 (CAYL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

Result

Result
OK
NG

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 17 CAN JUNCTION CONNECTOR)

CONNECT CONNECTOR

Reconnect the X114 No. 17 CAN junction connector.

Result

Proceed to
NEXT

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 18 CAN JUNCTION CONNECTOR)

*a	Front view of wire harness connector (to No. 18 CAN Junction Connector)
*b	Front view of DLC3
*c	to No. 17 CAN Junction Connector
*d	to Rear Steering Control ECU (w/ Dynamic Rear Steering System)
*e	to No. 8 CAN Junction Connector

Disconnect the No. 18 CAN junction connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
b10-9 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 17 CAN junction connector
b10-20 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 17 CAN junction connector
b10-10 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Rear steering control ECU*
b10-21 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Rear steering control ECU*
b10-11 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 8 CAN junction connector
b10-22 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 8 CAN junction connector

*: w/ Dynamic Rear Steering System

Result

Result	Proceed to
OK	A
NG (No. 17 CAN junction connector CAN main wire)	B
NG (No. 8 CAN junction connector CAN main wire)	C
NG (Wire to ECU or sensor)	D

REPLACE NO. 18 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 18 CAN JUNCTION CONNECTOR - NO. 17 CAN JUNCTION CONNECTOR)

GO TO STEP 16 Click here

CONNECT CONNECTOR

Reconnect the b10 No. 18 CAN junction connector.

Result

Proceed to
NEXT

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 8 CAN JUNCTION CONNECTOR)

Tech Tips

Before disconnecting the connectors, make a note of where it is connected.
Reconnect the connector to its original position.

Disconnect the No. 8 CAN junction connectors.

No. 8 CAN Junction Connector

Rear view of wire harness connector

(to No. 8 CAN Junction Connector)

Front view of DLC3

Wiring Color
Code	Color (CANH Side)	Color (CANL Side)	Connect to
P125	Y	W	Skid control ECU assembly
P126	B	W	Rack and pinion power steering gear assembly
P127	P	W	Front steering control ECU*1
P128	G	W	No. 18 CAN junction connector
P129	R	W	No. 1 CAN junction terminal*2
P130	BE	W	Driving support ECU assembly

*1: w/ Variable Gear Ratio Steering System

*2: w/ Pre-collision System

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
P125-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Skid control ECU assembly
P125-2 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Skid control ECU assembly
P126-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Rack and pinion power steering gear assembly
P126-2 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Rack and pinion power steering gear assembly
P127-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Front steering control ECU*
P127-2 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Front steering control ECU*
P128-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 18 CAN junction connector
P128-2 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 18 CAN junction connector
P129-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 1 CAN junction terminal
P129-2 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 1 CAN junction terminal
P130-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Driving support ECU assembly
P130-2 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Driving support ECU assembly

*1: w/ Variable Gear Ratio Steering System
*2: w/ Pre-collision System

Result

Result	Proceed to
OK	A
NG (No. 18 CAN junction connector CAN main wire)	B
NG (Wire to ECU or sensor)	C

REPLACE NO. 8 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 8 CAN JUNCTION CONNECTOR - NO. 18 CAN JUNCTION CONNECTOR)

GO TO STEP 16 Click here

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 18 CAN JUNCTION CONNECTOR)

Disconnect the cable from the negative (-) battery terminal.

*a	Front view of wire harness connector (to No. 18 CAN Junction Connector)
*b	Front view of DLC3
*c	to No. 17 CAN Junction Connector
*d	to Rear Steering Control ECU (w/ Dynamic Rear Steering System)
*e	to Central Gateway ECU (Network Gateway ECU)

Disconnect the No. 18 CAN junction connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
b10-9 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 17 CAN junction connector
b10-20 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 17 CAN junction connector
b10-10 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Rear steering control ECU*
b10-21 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Rear steering control ECU*
b10-11 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Central gateway ECU (network gateway ECU)
b10-22 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Central gateway ECU (network gateway ECU)

*: w/ Dynamic Rear Steering System

Result

Result	Proceed to
OK	A
NG (Central gateway ECU [network gateway ECU] CAN main wire)	B
NG (No. 17 CAN junction connector CAN main wire)	C
NG (Wire to ECU or sensor)	D

REPLACE NO. 18 CAN JUNCTION CONNECTOR

CONNECT CONNECTOR Click here

GO TO STEP 16 Click here

CONNECT CONNECTOR

Reconnect the b10 No. 18 CAN junction connector.

Result

Proceed to
NEXT

CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 18 CAN JUNCTION CONNECTOR)

Front view of wire harness connector

(to Central Gateway ECU [Network Gateway ECU])

Front view of DLC3

Disconnect the central gateway ECU (network gateway ECU) connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
P59-19 (CAYH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
P59-20 (CAYL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

Result

Result
OK
NG

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 18 CAN JUNCTION CONNECTOR)

CONNECT CONNECTOR

Reconnect the b10 No. 18 CAN junction connector.

Result

Proceed to
NEXT

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 17 CAN JUNCTION CONNECTOR)

*a	Front view of wire harness connector (to No. 17 CAN Junction Connector)
*b	Front view of DLC3
*c	to No. 18 CAN Junction Connector
*d	to Absorber Control ECU
*e	to No. 8 CAN Junction Connector

Disconnect the No. 17 CAN junction connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
X114-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 18 CAN junction connector
X114-12 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 18 CAN junction connector
X114-2 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Absorber control ECU
X114-13 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Absorber control ECU
X114-3 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 8 CAN junction connector
X114-14 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 8 CAN junction connector

Result

Result	Proceed to
OK	A
NG (No. 18 CAN junction connector CAN main wire)	B
NG (No. 8 CAN junction connector CAN main wire)	C
NG (Wire to ECU or sensor)	D

REPLACE NO. 17 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 17 CAN JUNCTION CONNECTOR - NO. 18 CAN JUNCTION CONNECTOR)

GO TO STEP 16 Click here

CONNECT CONNECTOR

Reconnect the X114 No. 17 CAN junction connector.

Result

Proceed to
NEXT

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 8 CAN JUNCTION CONNECTOR)

Tech Tips

Before disconnecting the connectors, make a note of where it is connected.
Reconnect the connector to its original position.

Disconnect the No. 8 CAN junction connectors.

No. 8 CAN Junction Connector

Rear view of wire harness connector

(to No. 8 CAN Junction Connector)

Front view of DLC3

Wiring Color
Code	Color (CANH Side)	Color (CANL Side)	Connect to
P125	Y	W	Skid control ECU assembly
P126	B	W	Rack and pinion power steering gear assembly
P127	P	W	Front steering control ECU*1
P128	G	W	No. 17 CAN junction connector
P129	R	W	No. 1 CAN junction terminal
P130	BE	W	Driving support ECU assembly*2

*1: w/ Variable Gear Ratio Steering System

*2: w/ Pre-collision System

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
P125-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Skid control ECU assembly
P125-2 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Skid control ECU assembly
P126-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Rack and pinion power steering gear assembly
P126-2 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Rack and pinion power steering gear assembly
P127-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Front steering control ECU*1
P127-2 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Front steering control ECU*1
P128-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 17 CAN junction connector
P128-2 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 17 CAN junction connector
P129-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 1 CAN junction terminal
P129-2 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 1 CAN junction terminal
P130-1 (CANH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Driving support ECU assembly*2
P130-2 (CANL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Driving support ECU assembly*2

*1: w/ Variable Gear Ratio Steering System
*2: w/ Pre-collision System

Result

Result	Proceed to
OK	A
NG (No. 17 CAN junction connector CAN main wire)	B
NG (Wire to ECU or sensor)	C

REPLACE NO. 8 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 8 CAN JUNCTION CONNECTOR - NO. 17 CAN JUNCTION CONNECTOR)

CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR)

Component with harness connected

(Central Gateway ECU [Network Gateway ECU])

Front view of DLC3

Reconnect all wire harness connectors.

Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the bus line shorted to GND is connected.

Click here

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
P59-19 (CAYH) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
P59-20 (CAYL) - P12-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

Tech Tips

If the resistance changes to 200 Ω or higher when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.
If the resistance does not become normal when the connector is disconnected from the ECU or sensor, check for a short to ground in the wire harness and repair or replace the wire harness or connector if necessary.

Result

Result
OK
NG

REPLACE ECU OR SENSOR

REPAIR OR REPLACE HARNESS OR CONNECTOR